North Korea’s Supreme Leader Kim Jong Un is believed to have ordered the execution of his onetime girlfriend, according to South Korea’s largest daily newspaper.

Seoul’s Chosun Ilboreports that the female singer Hyon Song Wol was arrested along with 11 other entertainers on August 17 for filming themselves having sex. They then sold the videos, some of which made it to China. The 12 people, who belonged to prominent performing troupes, were killed by firing squad on August 20 as their families looked on.

Hyon was best known for performing the song “A Girl in the Saddle of a Steed.” Kim met her a decade ago, but his father Kim Jong Il — then North Korea’s ruler — apparently did not approve of the relationship. Hyon subsequently married a member of the military while Kim married Ri Sol Ju, also a singer.

The Korea JoongAng Dailyquoted an intelligence official last July as saying that a rumor had circulated among the Pyongyang elite that Kim had resumed his romance with Hyon after his father’s death. The rumor was so rife that when Kim paraded a mystery woman by his side last year, the media had mistook her for Hyon when it was actually Ri.

A Chinese source told Chosun Ilbo that families of the executed appear to have been sent to prison camps in accordance with the country’s practice of punishing relatives.